Compounds such as N-(4-anilinophenyl)-methacrylamide have been prepared from methacryloyl chloride by methods as described in U.S. Pat. Nos. 3,658,769 and 3,852,350. Methacryoyl chloride is a severe lachrymator, relatively expensive, poisonous and highly corrosive.
Another process presently used for the production of alpha, beta unsaturated aryl amides is the ester process described in U.S. Pat. No. 3,907,893, which only gives maximum yields of 67 to 70%.
The synthesis of .alpha., .beta. unsaturated aryl amides is important since these compounds have been found to be effective polymerizable antioxidants.
In U.S. Pat. Nos. 3,907,893 and 3,852,350 the conversion of p-aminodiphenylamine is the limiting step. The p-amiondiphenylamine is the most costly reactant in the process, thus, an increase in the conversion would significantly lower the cost of the final product.
A great deal of effort has been expended in this area, however, the prior art does not suggest or disclose the process of the present invention wherein the product is produced via a dehydration of the .alpha. hydroxy isobutyramide of p-aminodiphenylamine.
There is a need for a process which does not involve the use of hazardous compounds such as methacryloyl chloride to produce methacrylamides.
The process of the present invention provides a method for preparing these amides and avoids the difficulties encountered in other preparations to date.